library(leaflet)
# Default Resolution
leaflet() %>% addTiles() %>% addTerminator()

# Custom Resolutions
leaflet() %>% addTiles() %>% addTerminator(resolution=1)
leaflet() %>% addTiles() %>% addTerminator(resolution=100)

# Custom Resolution + Custom Date and on a toggleable Layer
leaflet() %>% addTiles() %>%
  addTerminator(resolution=10,
                time='2013-06-20T21:00:00Z',
                group="daylight") %>%
  addLayersControl(
    overlayGroups = c("daylight"),
    options = layersControlOptions(collapsed = FALSE)
  )
